Pump

ABSTRACT

A pump, including a pump housing, defining an impeller chamber in fluid communication with a pump inlet and pump outlet. An impeller is rotatable within the impeller chamber and is attached to an adaptor shaft. The adaptor shaft is rotatably held in an intermediate housing that also serves as a mount for a drive source, such as an electric drive motor. A bearing held within the intermediate housing supports the adaptor shaft in both radial and axial directions and includes socket structure directly engageable with an output shaft of the drive motor. The socket structure includes clamping sections that are urged into frictional engagement with the output shaft of the drive source by a clamping device. The socket structure may include one or more slots for receiving a key carried by the drive shaft in order to provide a positive mechanical coupling between the drive source and the drive shaft. The shaft also includes tool engagement structure by which the shaft can be immobilized during an impeller removal procedure.

TECHNICAL FIELD

The present invention relates generally to fluid pumps and, in particular, to a method and apparatus for facilitating the connection between an impeller and impeller drive source in a centrifugal pump.

BACKGROUND ART

Centrifugal pumps are well known in the art and are used for many fluid pumping applications. For example, centrifugal pumps have been used to pump water from one water station to another. They may also be used in construction applications, i.e., to pump water from an excavation site. An example of the type of pump to which this invention pertains can be found in U.S. Pat. No. 3,898,014, which is hereby incorporated by reference.

Customers for this type of pump, may desire various types of driver sources for driving the pumping portion, i.e., impeller, of the pump. For example, customers may request electric motors of various horse powers, internal combustion engines or fluid pressure operated motors, both pneumatic and hydraulic. In the past, the adaptation or connection of various drive sources to the impeller has, in some cases, been difficult and not cost effective. In other cases the connection between the drive motor and pump has been a source of unreliability.

DISCLOSURE OF INVENTION

The present invention provides a new and improved pump construction which enables a variety of drive sources, such as electric motors, internal combustion engines and fluid pressure operated motors to be connected to the rotating components of a pump.

In the illustrated embodiment, an impeller forming part of a centrifugal pump is secured to an adaptor shaft. The adaptor shaft is rotatably supported within an intermediate housing by a bearing held within the housing and also locked to the adaptor shaft. The bearing supports both radial and axial loads during pump operation. The adaptor shaft has an outboard end adapted to engage the output shaft of the drive source. A clamping device, such as a split collar locks the adaptor shaft to the motor shaft. The adaptor shaft also includes structure engageable by a tool which prevents rotation of the shaft so as to facilitate removal of the impeller.

Additional features of the invention and a fuller understanding will be obtained by reading the following detailed description made in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a sectional view of a centrifugal pump assembly including a drive motor for rotating an impeller located within the pump;

FIG. 2 is a sectional view of an intermediate housing forming part of the pump assembly shown in FIG. 1;

FIG. 2A is an enlarged, fragmentary view of a seal forming part of the intermediate housing;

FIG. 2B is an end view of the intermediate housing;

FIG. 3 is a sectional view of the intermediate housing with internal components removed;

FIG. 3A is an enlarged, fragmentary view of a bearing receiving recess forming part of the intermediate housing;

FIG. 3B is an elevational view of the intermediate housing shown in FIG. 3;

FIG. 4 is a side view, partially in section, of an adaptor shaft forming part of the present invention;

FIG. 4A is a fragmentary, elevational view of an outboard end of the adaptor shaft shown in FIG. 4;

FIG. 5 is a schematic representation showing components made according to the present invention that are used to couple an output shaft of a drive motor with an impeller; and,

FIG. 6 is a fragmentary cut-away view showing an alternate construction of the adaptor shaft.

BEST MODE FOR CARRYING OUT THE INVENTION

FIG. 1 illustrates the overall construction of a centrifugal pump that incorporates the present invention. For purposes of explanation, the invention will be described in connection with a self-priming pump. The illustrated pump is of the type disclosed in U.S. Pat. No. 3,898,014 which is owned by the present assignee. A detailed explanation of the operation of a self-priming pump can be obtained by reference to U.S. Pat. No. 3,898,014.

It should be noted that the present invention can also be adapted to other types of centrifugal pumps and should not be limited to the self-priming pump construction illustrated.

By way of background, the illustrated self-priming pump includes an inlet or section port 10 to which fluid to be pumped is drawn and an outlet or discharge port 14 by which pumpage leaves the pump. A rotatable impeller 20 located in a volute chamber 20 a draws fluid though the suction port 10 and conveys it under pressure to the discharge port 14. A check valve 22 located at the suction port 10 closes upon pump shutdown and captures fluid within the pump. The check valve 22 facilitates start up of the pump after shutdown and reduces or eliminates the need for priming the pump. As more fully explained in U.S. Pat. No. 3,898,014, the disclosed pump has self priming capability, even in circumstances when the check valve fails to fully close. Again, this self priming capability is fully disclosed in U.S. Pat. No. 3,898,014.

The impeller 20 forms part of a removable rotating assembly indicated generally by the reference character 30. The rotating assembly 30 includes an intermediate housing 32 which includes a pair of flanges 32 a, 32 b. The flange 32 a is intended to mate with a flange surface defined by a pump housing 34. A plurality of bolts 35 are used to secure the flange 32 a to the pump housing 34.

The flange 32 b defined by the intermediate housing 32 provides a mounting surface for an impeller driver, such as an electric drive motor 36 shown in FIG. 1. The drive motor 36 can be replaced by other types of drive devices, such as an internal combustion engine or a fluid pressure operated motor.

According to the invention, the drive motor 36 is operatively coupled to the impeller by components (to be described) that are contained within the intermediate housing 32.

In prior art constructions, the shaft, to which the impeller 20 is mounted, is coupled to an output shaft of the drive motor by a coupling device which may permit some misalignment between the impeller shaft and the motor drive shaft. These couplers can be expensive and can be a source of wear and require periodic maintenance. The present invention addresses and eliminates the problem associated with motor-to-impeller shaft couplers by limiting the need for a separate coupler and by providing independent support for the shaft to which the impeller 20 is directly attached.

In an alternate prior art construction, special drive motors were used each having an elongate shaft to which the impeller 20 was directly mounted. In these latter constructions, the positioning of the impeller within the volute chamber, at least in some instances, was a function of the motor manufacturer. In these types of prior art constructions radial and axial loads exerted by the impeller 20 were transmitted directly to the motor. Misalignment or improper dimensioning of the drive source could result in improper clearance between the impeller 20 and its associated wear plate 90 (see FIG. 1). The present invention also obviates these problems associated with the prior art construction.

Referring also to FIG. 2, the impeller 20 is secured to the end of an adaptor shaft 40 by a bolt 42. Alternately, the impeller may be screwed directly onto a threaded section (not shown) of the shaft 40. Referring also to FIG. 2A, a seal assembly 44 inhibits leakage of pumpage out of the volute chamber 20 a. The seal 44 may be a face-type seal including non-rotating and rotating portions, an example of which is disclosed in U.S. Pat. Nos. 3,447,810 and 4,815,747 which are both incorporated by reference.

To provide improved seal life and dry running capability, the intermediate housing 32 defines an oil chamber 48 which keeps at least portions of the seal 44 immersed in oil, thus improving its life. The adaptor shaft 40 is rotatably supported and located both radially and axially within the intermediate housing 32 by a bearing 50, preferably a sealed ball bearing. The ball bearing 50 is secured to the adaptor shaft 40 by a pair of lock rings 52 disposed on either side of the bearing 50 and held in associated lock ring grooves 52 a formed on the adaptor shaft 40.

Referring also to FIGS. 3 and 3A, the bearing 50 is further positioned in a bearing recess 54 defined in a bearing housing portion 55 that forms part of the intermediate housing 32 and secured there by a lock ring 56 held in a groove 56 a. The bearing 50 supports both radial and axial loads during operation of the pump and reduces or eliminates radial and axial thrust forces from being transmitted to the drive motor 36, thus improving drive motor life. A seal 60 is held in the bearing support housing portion 55 and sealingly engages the adaptor shaft 40. The seal inhibits oil leakage out of the oil bath chamber 48.

Referring to FIGS. 4 and 4A, an outboard end 40 b of the adaptor shaft 40 defines a socket like structure 70 adapted to receive the end of a shaft 36 a of the drive source 36. In the illustrated embodiment, the socket 70 includes a plurality of slits or notches 72. In the illustrated embodiment, the outboard end 40 b of the adaptor shaft 40 includes four slits thus dividing the socket 70 into four clamping sections 70 a. To connect the outboard end 40 b of the adaptor shaft 40 to the shaft 36 a of the drive motor 36, the end of the drive motor shaft 36 is inserted into the socket end 70 of the adaptor shaft 40. A conventional split locking collar 76 is then positioned over the segments 70 a and then tightened as by a socket head screw or screws 78. By tightening the split collar 76, the individual segments 70 a are urged radially inwardly in order to clamp the outside of the drive motor shaft 36 a, thus rigidly locking the drive motor shaft 36 to the adaptor shaft 40. The coupling of the motor shaft 36 a to the impeller 20 using the above described components is shown in FIG. 5 with the intermediate housing 32 removed.

According to a feature of the invention, in order to facilitate maintenance on the impeller 20, the adaptor shaft includes multiple flats or other structure engageable by a tool. In the illustrated embodiment, a pair of flats 80 is formed, as by milling, onto the shaft 40. The flats 80 are positioned 180° apart and are adapted to be engaged by an appropriately sized open end wrench or other similar tool. The tool can be used to prevent rotation of the adaptor shaft 40 as the impeller securing bolt or nut 42 is removed (or to allow the impeller to be unscrewed from the shaft in those constructions that use a threaded shaft). Removal of the fastener 42 allows removal of the impeller 20 for replacement or to gain access to the seal assembly 44. Access to the flats 80 (and the collar 76) is provided by a pair of openings 84 formed in the intermediate housing 32.

The invention contemplates alternate constructions for providing the means to prevent rotation of the adaptor shaft 40. For example, the shaft itself may be hex-shaped or include a hex-shaped portion which could be engaged by a suitable tool. The shaft 40 may also be formed with three or more flats to facilitate engagement by a suitable tool.

FIG. 6 illustrates an alternate construction for the distal end of the adaptor shaft 40 which is capable of transmitting higher torques than the socket structure 70 shown in FIG. 4. In this alternate embodiment, an adaptor shaft 40′ includes a socket structure 70′ that provides a positive locking between the socket 70′ and an output end 36 a′ of a drive motor 36′. In this embodiment, the output shaft 36 a′ of the drive motor 36 includes a keyway 100. A key 102 carried in the keyway 100 is engageable by an associated slot 72 (shown in FIG. 4) defined between adjacent clamping sections 70 a′. In this alternate embodiment, the coupling between the adaptor shaft 40′ and the drive shaft 36 a′ does not rely solely on a friction engagement. The illustrated key arrangement mechanically couples the drive shaft 36 a′ to the adaptor shaft 40′.

The adaptor shaft 40′ shown in FIG. 6, also includes an alternate structure for immobilizing the shaft when the impeller 20 is to be removed. The embodiment shown in FIGS. 1-5 utilizes flats 80 which were engageable by a suitable tool. Referring to FIG. 6, the alternate adaptor shaft 40′ includes a recess 80′ that is engageable by a suitable pin-like tool 110 via an access hole 112 defined in the intermediate housing 32′. As seen in FIG. 6, a suitable tool may comprise a socket tool extension bar.

In the preferred construction of the present invention, the clearance between the impeller 20 and the wearplate 90 can be adjusted by shims 94 (see FIG. 1) placed between the pump housing 34 and the inner flange 32 a of the intermediate housing 32. Because the adaptor shaft 40 (to which the impeller 20 is secured) is located both radially and axially within the intermediate housing 32 by the bearing 50, dimensional variations in the motor shaft 36 a or the motor mounting do not affect the impeller-to-wearplate clearance.

As should be apparent, the present invention facilitates the adaptation of various drive sources to the rotating components of the pump. The use of the bearing 50 to rotatably support and locate the adaptor shaft 40 (to which the impeller is attached) substantially reduces the possible interaction between the construction/mounting of the drive source and the position of the impeller within the pump. The present invention also eliminates the need for separate, sometimes expensive couplers to couple a drive motor to an impeller as used in some prior art constructions.

Although the invention has been described with a certain degree of particularity, it should be understood that those skilled in the art can make various changes to it without departing from the spirit or scope of the invention as hereinafter claimed. 

1. A pump, comprising: a) a pump housing defining an impeller chamber; b) an impeller rotatable within said chamber and operative to pump fluid from a pump inlet to a pump outlet; c) an impeller drive shaft to which said impeller is attached and defining an axis of rotation for said impeller; d) a bearing rotatably supporting said drive shaft in both radial and axial directions, said bearing mounted within associated housing structure and held in said associated housing structure by a locking member which inhibits relative axial movement between said bearing and said associated housing structure; and, e) a distal end of said drive shaft including structure for engaging a rotatable output member of a drive source, whereby rotation of said drive source produces rotation in said impeller.
 2. The pump of claim 1 further including a clamping device for generating clamping forces between said distal end and said output member.
 3. The pump of claim 1 wherein said distal end defines a socket structure for receiving an end of said drive source output member.
 4. The pump of claim 3 wherein said socket further defines a plurality of clamping sections for frictionally engaging said end of said output member.
 5. The apparatus of claim 4 further including a clamping device for urging said clamping sections inwardly in order to engage an outer surface of said end of said output member.
 6. The apparatus of claim 5 wherein said associated housing structure is defined by a separable intermediate housing, said intermediate housing mounting said drive source.
 7. The pump of claim 6 wherein said intermediate housing defines an oil bath chamber.
 8. The pump of claim 7 further including a seal sealingly engaging said impeller drive shaft and operative to inhibit fluid leakage out of said oil bath chamber.
 9. The pump of claim 1 wherein said drive shaft includes engagement structure engageable by a maintenance tool whereby engagement of said structure by said tool resists rotation of said shaft during an impeller removal procedure.
 10. A centrifugal pump, comprising: a) a pump housing defining an impeller chamber in fluid communication with a pump inlet and a pump outlet; b) an impeller rotatable within said impeller chamber which upon rotation is operative to convey fluid from said pump inlet to said pump outlet; c) said impeller attached to an adaptor shaft and rotatable thereby; d) a seal having rotating and non-rotating portions for inhibiting fluid leakage out of said impeller chamber; e) said adaptor shaft rotatably supported by a bearing carried in an intermediate housing that is attached to said pump housing; f) said adaptor shaft defining a socket structure adapted to receive a drive shaft forming part of a drive source for the pump; g) said socket structure including clamping sections for frictionally engaging said drive source drive shaft; and, h) a clamping device for urging said clamping sections radially inwardly in order to frictionally engage said drive shaft.
 11. The pump of claim 6 wherein said an intermediate housing provides a mounting surface for said drive source.
 12. The pump of claim 11 wherein said intermediate housing provides access openings by which said tool engaging structure on said shaft can be engaged by a suitable tool.
 13. The pump of claim 10 wherein said bearing is held within a recess defined by said intermediate housing by a locking member and is secured to said adaptor shaft by a pair of shaft locking members which engage said shaft and which inhibit relative axial movement between said shaft and said bearing.
 14. The pump of claim 10 wherein said impeller is held to an impeller end of said adaptor shaft by a threaded fastener.
 15. The pump of claim 10 wherein said intermediate housing at least partially defines an oil chamber which provides an oil bath for at least portions of said impeller seal.
 16. The pump of claim 9 wherein said engagement structure comprises a pair of flats.
 17. The pump of claim 9 wherein said engagement structure comprises a recess.
 18. The pump of claim 3 wherein said socket structure defines a slot for receiving a key carried by said output member.
 19. The centrifugal pump of claim 10 wherein said socket structure defines a slot adapted to receive a key carried by said drive source drive shaft, such that said drive shaft is mechanically coupled to said adaptor shaft.
 20. A pump, comprising: a) a pump housing defining an impeller chamber; b) an impeller rotatable within said impeller chamber; c) an intermediate housing having one portion attached to said pump housing and another portion mounting a drive source for producing rotation in said impeller; d) an impeller drive shaft rotatably carried by said intermediate housing and operatively connected to said impeller, such that rotation of said drive shaft produces rotation in said impeller; e) a bearing rotatably supporting said adaptor shaft and mounted within said intermediate housing; and, f) said drive shaft defining drive source coupling structure at an end that is opposite the end to which said impeller is mounted, said coupling structure at least frictionally engaging an output member of said drive source.
 21. The pump of claim 20 wherein said coupling structure includes means for providing a keyed coupling between said drive shaft and said drive source. 